[Bug c/80631] [6/7/8 Regression] Compiling with -O3 -mavx2 gives wrong code

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80631

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-05-04
                 CC|                            |alan.hayward at arm dot com,
                   |                            |jakub at gcc dot gnu.org
   Target Milestone|---                         |6.4
            Summary|Compiling with -O3 -mavx2   |[6/7/8 Regression]
                   |gives wrong code            |Compiling with -O3 -mavx2
                   |                            |gives wrong code
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r230297.
Note, in C
  const int N = 8;
  int v[N];
is a variable length array, so unnecessarily pessimizing, you need to use
#define N 8
or
  enum { N = 8 };
or something similar instead for it to be a non-VLA.  In C++ it is not a VLA.
But fixing that doesn't help here.